Relay Board or whatever.

Our organist wants to get the chime keyboard controller out of the main organ. She would like to have it on a separate keyboard on the side of the organ. It basically is a bunch of hanging pipes which are hit by actuating a key which than activates a solenoid which hits the pipe. Basically a 1 contact key for each relay. I think it is 24 keys but I am not sure. So what I could have is an old electric keyboard to close the circuit directly for the solenoid or have a bunch of relays that would activate the solenoids. this is why I was looking at the Arduino boards. Anybody have any ideas?????

Why do you need Arduino for that? 24 switches to close 24 solenoid circuits. I don't see the need for relays or transistors or microcontrollers there.

Would probably need either relays or transistors to drive the solonoids - the kind of keys in most any sort of keyboard can't handle that kind of current, especially an inductive load.

But yeah - if you've got 24 buttons, and they're each actuating one thing, you may not need a microcontroller. Or is there some other sort of additional control needed?

You can find relay board with 8 relays & 8 relay drivers. They are made to work with the Arduino, but with 3 of those directly-controlled by the keyboard-switches, you shouldn't need an Arduino.

Or assuming they are DC solenoids, you can use a solid-state [u]solenoid drivers[/u], make with transistors or MOSFETs instead of relays.

You can also get solid-state relays, which are quieter, faster, and easier to use, than mechanical relays. But, they tend to be more expensive (although you save by not needing the driver circuit, and you may not need a circuit board).

You also have to make sure that solid-state relays are properly rated for AC or DC, and the correct voltage... They are a bit more "critical" than regular mechanical relays. i.e. Unlike mechanical relays, you can't use an AC solid-state relay in a DC circuit.

I think the "best" solution would be to build a "MIDI instrument" with the chimes (which could be done with the Arduino) and then she could use any standard MIDI keyboard. (You'd drive your relays/solenoids from the Arduino.)

That's more complicated (both hardware and software) than directly switching relays with a keyboard, but it seems like a more-professional more-permanent solution. If something goes wrong in the future, they could just swap-in a new keyboard and they wouldn't have to re-design from scratch. (But in that case, it would also be a good idea to build a spare Arduino/MIDI board.)

I don't know if modern pipe organs use MIDI, but I wouldn't be surprised if they do. It would be the easiest way to make a flexible/upgradable system.